During the requested four years of additional support we wish to continue our work on a wide ranging series of projects to elucidate several related problems: (A) The hypothalamic control of anterior pituitary hormone release with particular emphasis on the control of prolactin, growth hormone and ACTH. This area of research will involve the following projects: 1. further purification of the hypothalamic factor which stimulate and inhibit prolactin release and determination of their nature; 2. an attempt to determine if prolactin releasing factor can be separated from CRF since the physiological evidence is consistent with the concept that the two may be identical; 3. further study of the mechanism of action of the factors on the pituitary utilizing a newly developed preparation of dispersed pituitary cells in short-term culture; 4. more precise localization of the hypothalamic areas involved in prolactin, growth hormone, ACTH and TSH release; 5. further investigations of the role of the central monoaminergic systems in the control of the secretion of the above listed pituitary hormones; 6. delineating the role of prostaglandins in the control of the release of these pituitary hormones. (B) Purification and determination of the nature of the hypothalamic factors which can stimulate the release of glucagon and inhibit the release of insulin. An attempt to purify a hypothalamic natriuretic factor distinct from vasopressin and oxytocin. (C) Study of the effect of stress on the activity of the hypothalamic pituitary system with emphasis on the release of prolactin, GH and ACTH and a complementary of the role of these hormones in systemic changes associated with stress. (D) Examination of the physiological importance of extra-pituitary actions of GIF and TRF (and other factors if they become available).